Noise-attenuating laminate composite wallboard panel and methods for manufacturing same

ABSTRACT

A laminate composite wallboard panel is disclosed having multiple layers whose cross sections may contain internal and external non-uniformities and whose surfaces may be rough and non-uniform. The wallboard panel is similar in size and weight to a standard gypsum panel and can be handled and installed in a manner similar to such a panel. The wallboard panel also provides high degrees of noise attenuation, thermal insulation, fire resistance, shear strength, mold resistance and moisture resistance.

FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT STATEMENT

This invention was not developed in conjunction with any Federally sponsored contract.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to building materials and, more particularly, to a laminate composite panel for use in residential and commercial buildings.

2. Prior Art

Gypsum-based panels were first used to construct the interior walls of buildings nearly 100 years ago. Since then, the standard design of such panels has consisted of a gypsum core sandwiched between two layers of paper. Commercially available panels generally have gypsum cores ranging in thickness from ¼″ to ¾″, while the panels' large surfaces typically have widths of 48″ or 54″ and lengths ranging from 8′ to 12′ in one-foot increments. Within the construction trade, gypsum-based panels are interchangeably referred to as “drywall,” “wallboard,” “gypsum wallboard,” and “gypsum panels,” while the name “Sheetrock®” is a trademark of the U.S. Gypsum Company and is used to describe gypsum panels sold by that firm.

Since at least the 1950s, gypsum panels have been incorporated into laminate structures in attempts to address specific requirements of the construction industry, such as increased strength, fire resistance, thermal insulation, moisture resistance, mold resistance, and noise attenuation.

U.S. Pat. No. 6,901,713, for example, discloses a wallboard panel consisting of a standard gypsum panel bonded to a thin aluminum sheet. The principal object of this patent is to increase the shear strength, thermal insulation, and fire resistance over that provided by a standard gypsum panel.

U.S. Pat. Nos. 3,106,503 and 6,711,872 disclose paper-based honeycomb structures bonded on one or both sides to standard gypsum panels. These inventions provide increased shear strength and fire resistance.

U.S. Pat. Appl. No. 2005/0262799 discloses a gypsum panel onto which has been laminated a fiber-cement composition, thereby providing an increase in the composite structure's ability to resist physical abuse from objects (e.g., chairs, tables, toys) that come into contact with the panel.

U.S. Pat. No. 5,768,841 discloses a standard gypsum panel onto which is glued a metal sheet having a thickness between 0.015″ and 0.060″. This invention improves upon the in-plane and shear strengths provided by the standard gypsum panel.

U.S. Pat. No. 5,573,829 discloses a standard gypsum panel that is laminated with an aluminum-backed wood veneer. This invention provides a surface that may be debossed with decorative designs.

Over the last 10 years, the construction industry has placed increased importance on the development and application of materials that achieve high levels of noise attenuation. The excessive transmission of noise through walls, ceilings, floors, and doors is a major complaint of the occupants of virtually all buildings, including single-family homes, condominiums, apartments, office buildings, health care facilities, hotels, and schools. These complaints arise not only from noise generated by the occupants of neighboring units, but also from noise produced by exterior noise sources, such as roads, railways, and airports. In recent years, government agencies have set stringent noise-attenuation standards that govern the construction of both new and renovated residential and commercial buildings.

There are three basic approaches to enhance noise attenuation in walls and related structures. The first is the use of high-density materials and/or thick-walled construction to increase the mass of the wall. This approach is effective, especially for low frequency noise, but it is very expensive and decreases the amount of living space. The second approach is to decouple all or part of a wall panel from its support studs in order to reduce the mechanical transmission of noise energy from the panel to the studs. This decoupling approach can be relatively effective in controlled circumstances, but it is difficult to implement and is easily defeated post-installation by, for example, hanging fixtures on the wall. The third approach is to use energy-absorbing materials to damp out mechanical vibrations in the wall. Polymers, foams, and matted materials are commonly used for this purpose, but the use of any single material is often effective primarily over only a relatively narrow frequency range. More recently, however, noise-attenuating wallboards based upon composite laminates have been developed to dampen sounds over a broader frequency range.

ASTM International (“ASTM”; formerly the American Society for Testing Materials) has set forth a standard scale—the Sound Transmission Class (STC)—to rate the noise attenuation provided by various partition assemblies. The STC is a single-figure rating system that measures the acoustical performance of a wall partition assembly under typical conditions involving dwellings or offices. The higher the STC rating, the better the partition performance.

In determining the STC rating of a wall partition, two (or more) wallboard panels are used to construct a wall assembly separating the test area into two regions: the “test chamber” and the “receiving room.” Electronic equipment located in the test chamber is then used to generate sounds at standard frequencies and volumes, while additional equipment in the receiving room measures the sound that passes through the partition into the receiving room. The sound transmission loss between the test chamber and the receiving room is measured in decibels (dB) and plotted as a function of frequency in ⅓-octave bands from 125 Hz to 4,000 Hz. From the data, an STC rating is determined. The ASTM test standard for evaluating a partition assembly is ASTM E90-04, “Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements,” while the ASTM standard for determining the STC rating is ASTM E413-04, “Classification for Rating Sound Insulation.”

The prior art includes at least two wallboard inventions that achieve noise attenuation via gypsum-based composite laminates.

U.S. Pat. No. 6,758,305 discloses a two-layer laminate having a structural first face consisting of a gypsum panel (or plywood sheet) and a second face constructed from one or more of a variety of materials, such as recycled newsprint, perlite, fiberglass, EPDM rubber, or latex. The invention's noise-attenuation properties predominately arise from the device's second layer. This patent discloses that an STC rating of approximately 50 may be achieved through the invention.

U.S. Pat. Appl. No. 2005/0050846 discloses a multi-layer laminate having, as its wallboard embodiment, a 0.013″ core of galvanized steel sandwiched between layers of viscoelastic glue, each of which is attached to a gypsum panel. The invention achieves its sound-attenuation properties from the principle of “constrained layer damping,” which arises from the presence of the steel sheet that helps to constrain the laminate's layers of viscoelastic glue. Because of the steel sheet, however, a 4′×8′ panel of this embodiment weighs 108 pounds, whereas a single-sheet gypsum panel of equivalent thickness (i.e., ⅝″) weighs as little as 67 pounds. Moreover, the presence of the steel sheet in the invention requires that a power tool be used to cut panels. In contrast, standard gypsum panels have, for more than 90 years, been cut by a utility knife using a technique known as “score and snap.”

Although the prior art includes a multiplicity of gypsum-based wallboard laminates, few of those inventions disclose noise-attenuation characteristics that meet government noise standards, which standards typically require wallboard assemblies to achieve an STC rating of at least 50. The inventions that disclose noise-attenuation characteristics consist of multiple layers of the same or different materials bonded together, with each layer being uniform in material. While each layer is designed to serve a particular purpose within the laminate, the laminate's spatial uniformity in its plane reduces its effectiveness in attenuating noise, especially noise consisting of a broad range of frequencies. Moreover, those inventions that disclose noise-attenuation characteristics are substantially more difficult to handle and install than standard gypsum panels.

Hence, there is a need for a wallboard panel that largely mirrors the weight, handling, and installation characteristics of a standard gypsum panel, but that also meets governmental noise-attenuation standards.

SUMMARY OF THE INVENTION

The present invention is a composite laminate wallboard panel for use in place of standard gypsum panels. The invention is similar in weight to a standard gypsum panel and can be handled and installed in a manner similar to such panels. However, the invention also provides superior noise attenuation, thermal insulation, fire resistance, shear strength, mold resistance, and moisture resistance.

Noise attenuation in the current invention is enhanced over panels constructed from the prior art, since laminated layers of the current invention have rough, non-uniform surfaces and/or section properties. Surface non-uniformity may be accomplished by embossing, debossing, dimpling, scoring, kerfing, grooving, boring, perforating, scalloping, corrugating, routing, and/or performing other actions that produce surface non-uniformities, such as bonding or attaching in some manner patches of the same or different materials to the surface of the layer. The sizes, shapes, and spatial distribution of these surface features are generally non-uniform, and different types of features can be combined to yield the desired effect. Non-uniformity of the section properties of a layer may be accomplished by embedding one or more different materials and/or voids non-uniformly within the layer, or by constructing the layer as a patchwork of different materials. The sizes, shapes, material types, and spatial distribution of these embedded materials or voids are generally non-uniform, and different embedded features can be combined to yield the desired effect. Further, surface and section non-uniformity may be employed together in the same layer to yield the desired effect.

A preferred embodiment of the invention disclosed herein consists of a five-layer laminate structure arranged in the following manner. A core layer consisting of a thin sheet of absorbent paper is coated on each side with a layer of viscoelastic adhesive. On the exposed side of one these layers of adhesive is placed a standard gypsum panel, while on the exposed side of the other layer of adhesive is placed a fire resistant panel, such as one constructed from Magnesium Oxide (MgO), of dimensions that are similar to those of a standard gypsum panel.

In a second embodiment of this invention, the fire resistant panel of the preferred embodiment is replaced by a standard gypsum panel or a panel of a different material (e.g., polymer, metal, wood, or ceramic, wherein these materials may be in cellular or foamed forms) that has dimensions similar to those of a standard gypsum panel.

In a third embodiment of this invention, the core paper layer (and optionally either of the two viscoelastic adhesive layers) of the preferred embodiment is omitted from the construction of the invention.

In a fourth embodiment of this invention, the core paper layer of the preferred embodiment is replaced with a layer of a different material (e.g., polymer, metal, wood, or ceramic, wherein these materials may be in cellular or foamed forms) that has dimensions similar to those of the core paper.

In a fifth embodiment of this invention, one or both of the exposed surfaces of the preferred embodiment is augmented by a layer of viscoelastic adhesive and a standard gypsum panel (or a panel of one of the aforementioned alternative materials) that has dimensions similar to those of a standard gypsum panel.

In a sixth embodiment of this invention, the standard gypsum panels of the previously described embodiments are replaced by gypsum panels that have no paper backing on either or both of their surfaces or, alternatively, by gypsum panels that have a non-paper backing on either or both of their surfaces.

The thicknesses of the various lamination layers within a single panel of the current invention should be chosen to provide the desired level of noise attenuation, thermal insulation, fire resistance, shear strength, mold resistance, and moisture resistance. Suitable thicknesses of the panels made from gypsum, MgO, and the aforementioned alternative materials would be in the range from 1/16″ to ¾″. Suitable thicknesses of layers of viscoelastic adhesive range from 1/128″ to ⅛″. Suitable thicknesses of the layers of paper range from 1/128″ to 1/16″, although the thicknesses of the aforementioned alternative material layers may lie outside of this range.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments and characteristics of the present invention are illustrated by way of example, and not by way of limitation, in the following drawings.

FIG. 1 shows a five-layer laminar structure that was constructed with this invention and that attenuates the transmission of sound.

FIG. 2 shows a three-layer laminar structure that was constructed with this invention and that attenuates the transmission of sound.

FIG. 3 shows test results of the sound attenuation properties of the embodiment of this invention that is shown in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is intended to be exemplary only and not to in any way limit the scope or objective of the invention. The preferred embodiments referred to below describe a laminate composite wallboard system. This invention, however, is not limited to wallboards, but can be used in any application where a noise-attenuating building material is desired.

FIG. 1 shows a cross-section of a preferred embodiment of a wallboard panel constructed with the present invention, which wallboard panel is a five-layer laminate consisting of a standard gypsum panel 10 whose non-facing side is adjacent to a layer of viscoelastic adhesive 20. On the side of the viscoelastic adhesive 20 away from the gypsum panel 10 is a layer of absorbent paper 30. Then, on the side of the absorbent paper 30 away from the viscoelastic adhesive 20 is another layer of viscoelastic adhesive 40. Then, on the side of viscoelastic adhesive 40 away from the absorbent paper 30 is an MgO panel 50.

Some or all of the layers of this invention may be non-uniform in thickness, heterogeneous in material, and/or non-flat by virtue of being embossed, debossed, dimpled, scored, kerfed, grooved, bored, perforated, scalloped, corrugated, routed and/or otherwise made to be non-flat. All such non-uniform features may be distributed non-uniformly in the plane of the layer. For example, embossings and/or other non-uniform features may be used in combination and distributed randomly or have non-uniform dimensions.

The current invention introduces non-uniformity and heterogeneity in the plane of the panel to achieve greater noise attenuation via three mechanisms:

-   -   1. By developing more complex and non-uniform strain states in         energy (noise) absorbing materials, such as elastic adhesives,         the materials' natural damping capabilities may be enhanced and         better noise attenuation may be achieved over a wider frequency         range. These more complex strain states are generated by the         complex shapes of individual layers in the current invention.     -   2. Sound waves in the plane of the panel will be dissipated         better by the inherent heterogeneity in the panel. For example,         complex shapes that are non-uniform in the plane (as well as         patched materials) assist in deflecting in-plane waves, thereby         making the transmission of sound less efficient in these panels.     -   3. Non-uniform panels reduce energy transfer between parallel         panels by modifying modal deformations. When the vibratory mode         shapes of parallel panels are different, their energy transfer         capability (efficiency) is greatly reduced. The mode shapes of         these panels are affected by the non-uniform features in the         current invention.

FIG. 2 shows a cross-section of another preferred embodiment of a wallboard panel constructed with the present invention, which wallboard panel is a three-layer laminate consisting of a standard gypsum panel 60 whose non-facing side is adjacent to a layer of viscoelastic adhesive 70. On the side of the viscoelastic adhesive 70 away from the gypsum panel 60 is an MgO panel 80.

FIG. 3 shows test data representing the sound transmission attenuation (in dB) as a function of frequency using an industry-standard assembly constructed from the embodiment of this invention shown in FIG. 2. The thicknesses of the laminate components of said embodiment are: ⅜″ gypsum panel 60; 1/64″ viscoelastic adhesive 70; and 6 mm (0.236″) MgO panel 80. The test configuration was standard in the trade and was performed by an independent testing laboratory in compliance with the ASTM E90-04 and ASTM E413-04 standards using standard 2″×4″ wood stud construction.

Testing of the industry-standard assembly constructed from the embodiment of this invention shown in FIG. 2 produced an STC value of 52. It is well known in the field that an STC value of 34 can be achieved with an industry-standard assembly constructed with commercially available ⅝″ gypsum panels, which thickness is equivalent to the embodiment of this invention that was tested and whose test results are referred to above. Hence, the industry-standard assembly using the embodiment of FIG. 2 produced an 18-point STC improvement over standard gypsum panels. This STC difference indicates that an industry-standard assembly based upon the present invention transmits 71% less noise through a similar assembly based on an equivalent thickness of commercially available gypsum panels.

Various changes and modifications of the above-mentioned embodiments will be apparent to those skilled in the art. Hence, it is not intended that the scope of this invention be limited by the details of the above description. 

1. A laminar, sound-absorbing structure for constructing walls and ceilings, comprising: a plurality of layers wherein one or more of the layers has internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 2. The laminar structure of claim 1 wherein said plurality of layers consists of five layers, comprising: a first layer made of a selected material; which is contact with a second layer made of a viscoelastic adhesive; which is in contact with a third layer made of a selected material; which is contact with a fourth layer made of a viscoelastic adhesive; and which is in contact with a fifth layer made of a selected material.
 3. The laminar structure of claim 2 wherein the first layer comprises a gypsum panel.
 4. The laminar structure of claim 2 wherein the third layer comprises a sheet of absorbent paper.
 5. The laminar structure of claim 2 wherein the fifth layer comprises an MgO panel.
 6. The laminar structure of claim 3 wherein the third layer comprises a sheet of absorbent paper.
 7. The laminar structure of claim 6 wherein the fifth layer comprises an MgO panel.
 8. The laminar structure of claim 6 wherein the fifth layer comprises a gypsum panel.
 9. The laminar structure of claim 5 wherein the third layer comprises a sheet of absorbent paper.
 10. The laminar structure of claim 9 wherein the first layer comprises an MgO panel.
 11. The laminar structure of claim 3 wherein the fifth layer comprises a gypsum panel.
 12. The laminar structure of claim 3 wherein the fifth layer comprises an MgO panel.
 13. The laminar structure of claim 5 wherein the first layer comprises an MgO panel.
 14. The laminar structure of claim 1 wherein said plurality of layers consists of three layers, comprising: a first layer made of a selected material; which is contact with a second layer made of a viscoelastic adhesive; and which is in contact with a third layer made of a selected material.
 15. The laminar structure of claim 14 wherein the first layer comprises a gypsum panel.
 16. The laminar structure of claim 14 wherein the first layer comprises an MgO panel.
 17. The laminar structure of claim 15 wherein the third layer comprises a gypsum panel.
 18. The laminar structure of claim 15 wherein the third layer comprises an MgO panel.
 19. The laminar structure of claim 16 wherein the third layer comprises an MgO panel.
 20. The laminar structure in either of claims 1 and 14 comprising three or more layers where: at least one layer has internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform; and at least one layer is made of a viscoelastic adhesive.
 21. The laminar structure in any of claims 1, 14, and 20 wherein the first layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 22. The laminar structure in any of claims 1, 14, and 20 wherein the third layer is selected from a group consisting of paper, gypsum panels, MgO panels, metal, wood, ceramic, and polymers wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 23. The laminar structure in either of claims 1 and 2 comprising five or more layers where: at least one layer has internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform; and at least one layer is made of a viscoelastic adhesive.
 24. The laminar structure in any of claims 1, 2, and 23 wherein the first layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 25. The laminar structure in any of claims 1, 2, and 23 wherein the third layer is selected from a group consisting of paper, gypsum panels, MgO panels, metal, wood, ceramic, and polymers wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 26. The laminar structure in any of claims 1, 2, and 23 wherein the fifth layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 27. The laminar structure of claim 1 comprising seven or more layers where: at least one layer has internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform; and at least one layer is made of a viscoelastic adhesive.
 28. The laminar structure in either of claims 1 and 27 wherein the first layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 29. The laminar structure in either of claims 1 and 27 wherein the third layer is selected from a group consisting of paper, gypsum panels, MgO panels, metal, wood, ceramic, and polymers wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 30. The laminar structure in either of claims 1 and 27 wherein the fifth layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 31. The laminar structure in either of claims 1 and 27 wherein the seventh layer is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 32. The method of forming a laminar, sound-absorbing structure for constructing walls and ceilings which comprises: providing a layer of first material having two surfaces; placing a layer of viscoelastic adhesive onto one surface of said layer of first material; placing a layer of second material onto said layer of viscoelastic adhesive; applying selected amounts of pressure on selected portions of the layer of second material for selected amounts of time; and heating/cooling said layers of laminar structure at selected temperatures for selected amounts of time.
 33. The laminar structure of claim 32 wherein the layer of first material is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 34. The laminar structure of claim 32 wherein the layer of third material is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 35. The method of forming a laminar, sound-absorbing structure for constructing walls and ceilings which comprises: providing a layer of first material having two surfaces; placing a layer of viscoelastic adhesive onto one surface of said layer of first material; placing a layer of second material onto said layer of viscoelastic adhesive; placing a layer of viscoelastic adhesive onto the exposed surface of said layer of second material; placing a layer of third material onto said layer of viscoelastic adhesive affixed to said layer of second material; applying selected amounts of pressure on selected portions of the layer of third material for selected amounts of time; and heating/cooling said layers of laminar structure at selected temperatures for selected amounts of time.
 36. The laminar structure of claim 35 wherein the layer of first material is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 37. The laminar structure of claim 35 wherein the layer of second material is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform.
 38. The laminar structure of claim 35 wherein the layer of third material is selected from a group consisting of gypsum panels, MgO panels, wood, plywood, metal, fiber glass, polymers, fire retardant panels, and high-density mat materials wherein said materials may be cellular or foamed and have may have internal and/or external non-uniformities and/or surfaces that are rough and/or non-uniform. 